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Chapter 5 Study Outline-ITEC100-20 1 Fundamentals of Telecommunications Communications – the transmission of a signal from a sender to a receiver by way of a medium such as wires or radio waves. Communications Medium – anything that carries a signal between a sender & receiver 1.1 Telecommunications and Data Communications Telecommunications -- refers to the electronic transmission of signals for communications. Examples: Some telecommunications devices that we interact with on a daily basis include telephones, radios, TVs, and computers. Data communications -- a specialized subset of telecommunications, refers to the electronic collection, processing, and distribution of data, typically between computer systems Telecommunications network -- connects communications and computing devices Computer network -- a specific type of telecommunications network that connects computers and computer systems for data communications This chapter discusses the following components of telecommunications: Networking media: Anything that carries an electronic signal and creates an interface between a sending device and a receiving device. Networking hardware devices and networking software: Work together to enable and control communications signals between communications and computer devices. 1.2 Characteristics of Telecommunications The characteristics of telecommunications components should be analyzed in terms of speed, quality, and convenience. Telecommunications can allow people to be more productive. For example, being able to access and respond to e-mail during an hour-long daily commute on the bus or train frees up an hour later in the day for going to the gym or some other productive activity. 1.2.1 Types of Signals If we measured the voltage on a telephone wire during a conversation, we would see something like Figure 5.4a. Notice that the figure shows a signal that continuously changes over time. This type of continuous fluctuation between high and low voltage is called an analog signal. In contrast, if we measured the voltage on cables used to connect PCs, we would probably see something comparable to Figure 5.3b. The signal in Figure 5.3b at any given time is either high or low. This type of discrete voltage state (either high or low) is called a digital signal. The two states are used to represent the state of a bit, high for 1, and low for 0. 1.2.2 Transmission Capacities Signal Frequency -- speed at which an electronic communications signal can change from high to low is called the signal frequency A faster frequency means a faster data transmission rate. Signal frequency is measured in hertz (Hz), or cycles per second. In computer networks, the data transmission rate is also referred to as the bandwidth and is measured in bits per second (bps). Today’s bandwidth options fall into one of two categories: narrowband or broadband. Bandwidth Options Broadband: Media advertised by Internet service providers as “high-speed.” Narrowband: Any medium with a speed less than 200 Kbps, typically the speeds delivered by a 56 Kbps dial-up modem connection. TEAM NAME________Assigned to 4 girls & a guy – I didn’t get this from you??? Members Present / Roles _______________________________ 2 Networking Media, Devices, and Software 2.1 Networking Media 2.1.1 Physical Cables 2.1.1.1 Type of Cables 2.1.2 Twisted-pair cable: Coaxial cable: Fiber-optic cable: Radio Signals And Light TEAM NAME: Spartans Members Present / Roles: Jenna Hafey, Kyle Bailey, Kristen Redwine, Thomas Lloyd, Spencer Moser 2.2 Networking Devices Modem, Network Adapters, Network Control Devices 2.2.1 Modem Modem- modulates and demodulates signals from one form to another, typically for the purpose of connecting to the Internet o Can either be internal or external Cable Modem-provides Internet access to PCs and computer networking over a cable television network o Typically an external device DSL modem- is similar to a cable modem, and provides high-speed Internet service over telephone lines 2.2.2 Network Adapters A computer circuit board, PC card, or USB device installed in a computer so that the computer can be connected to a network. o Network Adapters come in two basic varietites: 1. Network Interface card: Circuit board or PC card that, when installed, provides a port for device to connect to a wired network with traditional network cables. 2. Wireless Adapters: Can be circuit board, PC card, or an external device, which is USB device, that provides an external antenna to send and receive network radio signals. 2.2.3 Network Control Devices Hubs:. Small electronic box used as a central point for connecting series of computers. Switches: Make it possible for several users to send info. Over a network at the same time slowing each other down Repeaters: connect multiple network segments, listening yo each segment and repeating the signal heard on one segment onto every other segment connecting to the repeater. Bridges: connect 2 or more segments and helps regulate traffic Gateway: network points that act as an entrance to another network Routers: advanced network components that divide a single network onto 2 logically separate network Wireless access point: allow wireless devices to connect to a network Firewall: filters info. Coming onto a network to protect the network Sometimes network control devices can be combined in a single unit. An example would be a home computer network might incorporate a device that includes a router to create a high speed internet connection, a switch to share internet access over a wired network and connect computers and a wireless access point to connect wireless devices. Example from the Web: How Stuff Works.com “How Modems Work” http://computer.howstuffworks.com/modem1.htm This is relevant to our topic because this site explains where modems originated from and how they have advanced and developed. It also explains how modems connect to the Internet Service Provider and transfer TCP/IP packets between your computer and your ISP. This website also gives you links to the top selling modems and links to websites where you can buy them from. TEAM NAME The Highlanders Members Present / Roles Leader: Franklin Text Researcher: Briana Kirby, Micheal Mitchell Web Researcher: Christel Micheal Recorder/Submitter: Kristopher Teaford 3 Wireless Telecommunications Technologies Wireless communications and computing can be found everywhere. It is expected by the year 2007 there will be more than 2 billion global mobile subscribers taking advantage of wireless communications and information services. Wireless technology is leading us into the era of communications and computing that can occur anywhere at anytime. Wireless technology allows you to connect to public and private networks, access TV, music and games, find your current location on a map and access numerous information services. www.cwt.vt.edu/faq/default.htm This site answers questions to wireless terms, its capabilities and regulations. 3.1 Cell Phone Technologies Cellular Network: A radio network in which geographic area is divided into cells with transceiver antenna (tower) and station at the center of each cell, to support mobile communications. Cellular Carrier: a company that builds and maintains a cellular network and provides cell phone service to the public. EX: Verizon, Sprint, T-Mobile, AT&T. Each 3.2 Pagers Pagers: small, lightweight devices that receive signals from transmitters. The most basic pager simply, beeps, flashes or vibrates to get the attention of the user. The first commercial pagers were used in the St. Thomas Hospital in England (mid 1950s) Today businesses such as restaurants, emergency room and golf courses use pagers. www.anesithesia-analegesia.org/cgi/content/full/101/1393 This site provides information on phones/pagers and how they are useful in hospital. 3.3 Global Positioning Systems GPS: uses satiates to pinpoint the location of objects on earth. Using a GPS receiver and a network of 24 satellites, the GPS can tell you the exact location of the receiver on the earths surface. The GPS satellites orbit the earth in such a way that at any given time and location on the earth, four satellites are visible to a GPS receiver. EX: Many cars such as Lexus, use GPS systems so that the driver can find maps and directions to were they are going. www.colorado.edu/geography/gcraft/notes/gps/gps_f.html This site gave an overview of GPS systems. 3.4 Wireless Fidelity and WiMax WiMax: the next generation wireless broadband technology that is both faster and has a longer range than Wi-Fi. A WiMax atena has a 31 mile range and is perfect technology to provide citywide high-speed internet access. WiMax is used in many large cities such as, LA, New York, Chicago and Las Vegas. Wireless Fidelity: Wireless Fidelity: Wireless networking technology that makes use of access points to wirelessly connect uses to network within a range of 250-1000 feet. By positioning wireless access points at strategic locations throughout a building, campus or city, Wi-Fi users can b continuously connected to a network and Internet, no matter where they roam on the premises. EX: Starbucks uses a Wi-Fi network so that while customers drink coffee they can also enjoy using the internet on their laptops. Radford University also uses WiFi so that students can be anywhere on campus and access the internet. TEAM NAME Cardinals Members Present / Roles Anna, Rick, Sarah, Will Wireless Telecommunications Technologies (continued) 3.5 Bluetooth wireless technology that enables a wide variety of digital services to communicate directly Examples: digital camera, dvd players, cars, computers, headphones, speakers, MP3 players, microwaves URL:www.bluetooth.com Site name: Bluetooth Relevant: based on the topic 3 Points: enables a wide assortment of digital devices to communicate directly with each other over short distances, communicate directly with each other in pairs, and up to seven devices can be paired simultaneously 3.6 Infrared Transmission utilizes infrared rays to send data over a short distance wirelessly Examples: TV remotes, notebooks, handheld computers URL: www.mzoop.com Site name: Universal Payment Service Relevant: focuses on infrared transmission 3 points: requires a direct line of site connection operates at short distances, uses light rather than broadcast technology, and makes ideal for secured data transmissions that you do not want to have intercepted by spying devices 3.7 Radio Frequency Identification uses tiny transponders in tags that can be attached to merchandise or other objects and read using an RFID receiver or reader for the purpose of identification Examples: Delta airlines, baggage handling systems to track bags URL: www.rfidjournal.com Site name: RFID Journal Relevant: focuses on RFID news and views 3 points: too expensive and too limited to be practical, reader sends out electromagnetic waves, which the antenna receives, and an 4 Networks and Distributed Computing 4.1 Computer Networking Concepts Examples: local resources (file, drives, printer), network resources (workstation accesses over the network) URL: http://compnetworking.about.com/od/basicnetworkingconcepts/Networking_Basics_Key_Concepts_in_Computer_ Networking.htm 3 points: transparency provides a more intuitive computing environment by hiding the underlying system from the user, people get a sense of working on one extremely powerful computer, and workstations have access to both local and network resources 4.1.1 Distributed Computing a computing environment that includes multiple remote computers that work together to solve problems and provide services Examples: database servers, print servers, file servers URL: http://www.extremetech.com/article2/0%2C1697%2C11769%2C00.asp 3 points: large enterprises use distributed computing, application servers store programs such as word processors and spreadsheets and deliver them to workstations, and a thin client includes a keyboard, a mouse, a display, and a small unit system that supplies enough computer power that connects a device to the server TEAM NAME: Tech Squad -- Katie Ramos, Brittany Gerald, James Harris, Drew Polhanus. Members Present / Roles: Katie: Leader, James: Presenter, Brittany and Drew: Researchers. 4.2Network Types Personal Area Network Local Area Network Intranet Virtual Private Network Metropolitan Area Network Global Networks Wide Area Network 4.2.1 Personal Area Network (PAN) The wireless interconnection of personal information technology devices within the range of an individual. Can also be wireless. Connects cell phones to the internet. o Ex: Bluetooth. 4.2.2 Local Area Network (LAN) Connects computer systems and devices within a common geographic area Ex: Connects workstations and personal computers, can access data and devices anywhere on the LAN such as a printer. Virtual Private Network (VPN) - Uses the Internet to connect an organization’s networks dispersed around the world into one large intranet. Intranet- A private network that utilizes Internet and Web protocols and software. 4.2.3 Metropolitan Area Network (MAN) Connects networks within a city or metropolitan-size area into a larger highspeed network. Typically used wireless infrastructure or optical fiber connections to link their sites 4.2.4 Wide Area Network (WAN) Connects LANs between cities, cross country, and around the world using microwave and satellite transmission or telephone lines Uses routers and public communications links Largest and most well known example is the internet. 4.2.5 Global Networks (International Network) Is a WAN that crosses National boundaries TEAM NAME: 4 Girls and a Guy Members Present / Roles: Andrew Cook (web researcher)(Presenter), Morgan Yellman (text researcher)(Leader), Kellie Wingold (text researcher) and Callie Martin (text researcher)(Recorder/Submitter) 5 Networking Media, Devices, and Software Telecommunications networks can support voice or data communications, and some can support both. No matter what type, the communications that take place on these networks require networking media, hardware and software. To fully understand the benefits of various network technologies you must learn the strengths and weaknesses of their components. This section compares and contrasts different types of network media. 5.1 Networking Media Networking Media: Anything that carries an electronic signal and creates an interface between a sending device and a receiving device. Examples of Networking Media: o Wireless Internet Networking Devices: Hardware components that together with networking software enable control communications signals between communications and computer devices. An example would be a modem or network adapter Networking Software: software components that work together with hardware components to enable and control communications signals between communications and computer devices. An example would be an Ethernet. 5.1.1 Physical Cables Different physical cables offer a range in bandwidth from narrow to broadband Cables have an advantage over wireless options because cables have a higher transfer rate and are more secure. The disadvantage of cables is their physical presence. 5.1.1.1 Type of Cables Twisted-pair cable: for traditional phone lines, twisted pairs of wires in plastic sheathing Coaxial cable: Used for home cable TV, thick copper wire (faster than twisted pair) Fiber-optic cable: Thin strands of glass are used to send light beams (highest bandwidth cable, most expensive) 5.1.2 Radio Signals And Light Radio Waves-Electromagnetic waves transmitted through the air at various frequencies Radio waves use different frequencies to carry many types of information. Some examples include: o AM & FM Radio o Short Wave and CB Radio o Television Broadcasts o Garage Door Openers o Baby Monitors o Cordless Phones o Cell Phones o Radio Controlled Cars and Airplanes o Global Positioning Systems o Wireless Computer Networks o Microwave Communications URL:www.science.hq.nasa.gov/kids/imagers/ems/radio.html This site is relevant because it shows you many kinds of radio waves and how they work.